Underfeed stoker



Dec. 22, 1931. R s, RlLEY 1,837,729

UNDERFEED STOKER Filed June 22 2 2 Sheets-Sheet 1 KATHARINE H. BILLY EXECUTRIX OF THE WILL OF R. SANFORD RILEY INVENTOR, DECEASED,

WITNESS I BY a. I Ah EY Dec. 22, 1931. s RILEY 1,837,729

UNDERFEED STOKER Filed June 22 1925 2 Sheets-Sheet 2 [(ATHARINE H. RILEY EXECUTRIX OF THE. WILL OF R. SANFORD RJLEY INVENTOR, PECEASED,

WITNESS Q q W I A l'T NEY an adjustment of thestroke.

r minute. v j

Various arrangements have been dISClOSBd" Patented Dec. 22, 1931 UNET s'rmuzis PATENT OFFICE ROBERT sAnEoRn RILEY, nEcEAsEn LATE or WORCESTER, msseonusnr'rs, BY

KATHARINE H. RILEY, EXEGUTHIX, OF WORCESTER, MASSACHUSETTS, ASSIGNQR RILEY STOKER CDR'PORATION, OF NGRCESTEZR, BTASSAGHUSETTS, A COREORATION OF MASSACHUSETTS 7 UNDERFEED sToKER Application filed June :22,

This invention relates to stokers-of the.

underfeed type, and more particularly to bed and a discharge of the incombustible refuse.

In such stokers as heretofore manufactured the reciprocating retort sides have been driven directly by the fuel feeding ram and at the same rate as the ram. As it isundesirable that the retort sides should have as great a movement as the ram, lost motion connections have been introduced to permit This results in the retort sides remaining stationary during a large part of the ram stroke,'and the benefits to be derived from a more continuous movement are lost. With some fuels, particularly those which tend to form large olinkers and obstruct the flow ofair through the'fuel bed, it is of great advantage to move the retort sides at a higher rate than the ram, that is, at agreater number of strokes per in certain of my prior patents, in accordance with which the side bars have been rec1procated at a different rate from that of the ram,

but such prior constructions have not em V illustrating one embodiment of the invention, the section being taken on the line l1' of bodied the correct principles of stoker operation and so have not proven practical. I

It is accordingly the primary object of this invention to overcome the difficulties heretofore met and to provide a stoker construction so arranged that the retort sides may move relative to the coal feeding ram in such a manner that the fuel bed maybe kept well broken up by a slicing action occurring between the retorts and adjacent to the tn "With this and other objects in view as will 1926. Serial No. 117,721.

be apparent to one skilled in'the art, the

invention resides in the combination of parts set forth in the specification and covered by c the claims appended hereto. v a In accordance with the invention, anunder- .feed stoker is provided in which the 'fuel is fedinto the retorts from a hopper by means of reciprocating rams. Theretort side walls, including tuyeres near their upper limits, j

are arranged to reciprocate also, the bottom of the retorts preferably rernaining'station' ary. Means are provided for reciprocating these retort sidewalls at a rate dlfierent from,

and preferably greater than, that of the rams.

Means are also provided'foradjusting the length of stroke of the retort s de walls, and giving them a. continuous motion when ,de-

sired; 'Means are also provided for stopping the retort side walls independentlyof the ram 1n case an exceptional reslstance is ention may be arranged adjacent to the lower end of the retort, and this may be attached to'the retort sides so as" to move therewith.

Suitable means, such as moving dump plates, may be so located as to cause a discharge of 'Fig.2;dw,

Fig. 2is a' sectional plan ofthe stoker, with parts broken away;

Fig. 3 is a detail showing the method of sup porting the retort sides at the furnace front; Fig. 4 is a side elevatiomwith parts broken away, of the stoker gearbox; and

Fig. 5 is a perspective view of the crank shaftwhi'chd'r'ives the retort sides;

. j countered. If desired, an overfeed grate sec Referring to the drawingsin whichlike: I

The embodiment of the invention illustrated in the drawings comprises a-stoker having three retorts 7 8 and 9. A hopper 10 is suitably arranged adjacent to the front wall 11 of the furnace so as to provide ajreceptacle for the fuel." The fuel is pushed intothe retorts by means of reciprocating rams l2, driven by connecting rods 14 and "crankshaft '15. In a stoker having thre,e-retorts,'this' crankshaft ispreferably provided with throws. arranged 1 degrees apart, so as to distribute the load on the ram moving mechanism. In the form illustrated, the'crankshaft is provided with a worm gear 16 driven by worm'17, which in turn sis-driven from a suitable source of power. V a The stoker retorts may be formed by stationary retort bottoms 19 and'movable retort side walls,'the latter comprising ide-bars 20 and air admitting tu-yere blocks 21 mounted thereon. These are preferably split on the,

line between retorts, so that the retortside'of adjacent retortsmay have relative motion.

The side bars 20 may be supported at their outer endsjon 'rods 22 arranged to .slide through holes inthe ram cases At their Y inner ends they are preferably" attached to shoes 24 arranged to slide on'fiXed base plates .26, which are bolted to I-beams 27.. Theends of these I-beams rest on the foundations of f the furnace sidewalls. Adjacent to'the lower 0at the front onpipecolumns 36 endsofthe retorts, and mounted onthe side bars so as to reciprocate therewith, are overfeed grate 'sections2 8, which extend across the entire width of each retort, from one side bar to another, Hinged to the sliding shoes 24 and arranged tomove therewith and to partially close the opening adjacent to the bridge 7 Wall 29 are dumppla tes i The movement of these plates produces a constant discharge of ash from the furnace, and their position can be adjusted or a complete dump made by turning dump shaft 31, and so'moving rack .32 longitudinally by its engagement with pinion 33. At the front of the stoker a front plate is provided so as to form an air chamber for the introduction offorced draft from a suitable fan. The stoker may be supported The constructlonas hereto-foredescribed is well linownin the art, and similar stokers the sides of adjacent retorts, the :fuelbed, -wh ch tends tocoke overmoreorless sol];

when banked, w1ll be quickly broken up so as are disclosed in the patents to Riley Nos.

1,090,651and 1,322,822 'Inorder to produce a more thorough agitationiof 'thefuel-bed than has been possible heretofore, means have been provided for reciprocating the retort side walls continuously when desired and at a higher rate than therams. It i s-highly desirable at certain times to give these retort sides a comparatively rapid continuous motion. This is particularly true when the fire is in a banked condition and there is a sudden heavy load demand, requiring the boiler. being fired to-be thrown on the line in the shortest possible time. By moving the retort sides rapidly and continuously, and especiall v by providing for relative motion between.

to allow air to pass thereth r'ough'. In this way the boiler can be brought to a high rating very quickly.

The drawings illustrate ;cne means by the stroke of the rams;

relative motion between the sides of adjacent retorts, and lines of cleavage will be formed in the fuel bed over the tops of the tuyeres This provides an opening for the passage of air and an exit for the hot gases, which other-v wise tend to strike back and injure the fuel 1 supporting surfaces. -Th1s relative motion between retorts is also of the. greatest im,

portance in keeping the fuel bed agitated, and

ers. V I

Therod 41 passes through a slot 43 in the front, plate 35, and. in order, to prevent the escape of air into the boiler room through 'this slot, a closing plate 44is provided. This plate hasan opening only sl ghtly larger than the rod 41, through which the latter passes. In operation the rod 41 moves up and down in the slot 43, andqplate44 moves with it, being prevented from movingaway from the front plate by guides 45.

I Has highly desirable that means should be providedfo-r varying the stroke of the retort sidewalls, and for giving "them acontinuous mot-ion when the stroke'is adjusted to the maximum amount. In this way, low,

portions of, the'f'uel bed can bequickly filled- 111. .Moreover, by producing rapid agitation of thefburning fuel, it is possible to meet sudden demands for steam from the boiler be ng fired.

. In order to accomplish this, crankshaft 42 is arranged to driveeach connecting rod '41- preventing the formation of large. clinln' by means of ablock46 arranged toslideon;

the rod between collars 47. and 4 8, which are fixed on the rod by pins 49, and 50 respectively, These pins pass throughholes in the rod and collars. As shown in Fig. 4, several holes may be provided in the rod, so that the position of collar .47 may be varied, and the length of the sidebar stroke adjusted. If desired, collar 47 may be located closely adjacent to block 46, so that the retort sides willbe given a continuous reciprocating motion. Pins 47 and 48 are preferably of suflicient strength to drive the side bars under ordinary conditions.

* butso noportioned that they'will shear if any exceptional resistance is encountered during either aforward'or back-wardistroke,

so as to prevent any further damage to the stoker driving mechanism. Such a construetion is of the greatest advantage, as is 'well known to those skil'ledinthe-art; :At times, hard clinkers become wedged against the bridge wall so as to impede the motion of the side bars. There is also a danger of tramp 'iron from thecoal becominglodged between the relatively moving tuyeres. Without some safety device, such an occurrence might cause destruction of expensive parts of the machine. It isevident that the shearing pins shown in Fig. 4: can be replaced very easily and cheaply after the obstru'ction is removed.

On crankshaft 42 is mounted a .worm gear 52, which is driven'by a worm 53." Norm '53 is keyed to shaft 54, which ism'ounted in suitable bearings 55; Shafth f preferably. ex-

tends through worm 17 also, and this construction affords an advantage in that the twoworms .can be made of opposite'hand and their thrusts will hence to a certain extent counteract each other. It is also possible in this way to simplify the construction and drive the rams and retort sides from the same source of power and in timed relation. Each worm is shown in Fig. 4 as being constructed with a single thread, gear 52 as having 16 teeth, and gear 16 as having 24 teeth. It is obvious then that under these conditions, the retort sides will move at a different rate from the rams. In the case illustrated, the sides of any particular retort will make three strokes while the ram is making two; This ratio can of course be made anything desired.

A suitable driving means is connected to.

the stoker shaft 60, and this in turn drives worm shaft 54 through suitable gearing, not

shown. If desired, this gearing may be of the two speed type, as disclosed in the patent to Taylor No. 1,486,311. In this case, the lever 61 serves as a means for stopping the stoker, or for changing from one speed to another.

The operation of the stoker will be apparent from the above disclosure. Fuel, usually coal, is fed from the hopper 10 into the retorts by the reciprocating rams 12. In the retorts the Volatile constituents of the fuel are driven oil by the heat of the fire above, and these gases pass upward through the layer of burning fuel, where they are consumed. After the gases are driven off, the remaining coke is gradually forced upward and rearward, past'the streams of air issuing from the openings in the tuyeres 21. The reciprocating retort sides keep the fuel bed well broken up and continually feed it rearward towards the bridge wall 29. The combustible is almost completely burned out on the overfeed grate sections 28, which move with the retort sides, and feed the ash and clinkers on to the dump plates 30. Here the incombustible matter is continuously agitated, crushed, and ejected from the furnace.

The stoker is driven from any suitable source through'fsuitable gearing, causing the two crankshafts to revolve intimed'relation. In

the embodiment illustrated, the retort sides of any particular retort make three strokes while the correspondingram is smaking two. N strokes. In .other words the.side-wallsfgo in, out, and in, while theram is going in and' out. Relative motionbetweenadjacent retort sides is provided .for'in thedesign of the crankshaft. The relative'position ofithe various parts at :onepoint-inmthe cycle is illustrated in Fig. 2, and their respective directions of motion are shown by arrows.

In retort 7, the ram'has moved a shortdis-l tance onits',rearwardistroke towards the furnace, and the retort sides have movedyay' short distance on their forward stroke. yIn.

retort 8, the ram has just started-its: forward stroke, and the retort sides have just started their rearward-stroke; In retort 9, the ram ha's near'ly completed its forwardstroke and the retort sides have nearly completed theirrearward stroke. a In Fig. 1,and. Fig. 2,'the

retort'sides are illustrated as moving con tinuously, without lost motion. Their stroke.

can be changed easily, as shown in Fig. A,

by moving pin 49 and collarAT to another hole. It will beobserved that this construction causes the reciprocable partstoimQve in atimed relation and with a frequently re curring cyclic movement, which in the illusa tration given has a 3 to 2 ratio, the ram making two full double strokeswhile the side bars move three double strokes to complete the cycle. A non-cyclic movement, or

one recurring only at infrequent intervals,

may develop undesirable characteristics in.

the-condition of the fuel bed. Y

I It will be evident to those skilled in the art, that the invention provides an underfeed stokerby means of whi'ch thefurnace conditionscan'be more easily controlled than bystokers as heretofore disclosed. I Simply byadjusting the side bar motion from a short intermittent stroke to. a comparativel'y long continuous stroke, the: fuel bed can be built up,.leveled, orithinned out as desired, clinkers can be.:easily broken up and fedto the dump plates, .and a banked fire quickly brought into a condition; to carry a" heavy load.

entisz Having'thus described the invention SANFORD RILEY, deceased,what is claimed as new and desired to'securejb'y Letters Pat the fuel bed, a ram reciprocable to move fuel into'the retort, and means to move the ram and the side walls at different rates andin a manner to provide' considerable relative fre quently; recurring cyclic movement between" 2. {An underfeed stoker comprising having stationary i bottoms and movable side walls, reeiprocable rams for feeding fuel into 1 said retorts, means for'actuating said rams," and means forreciprocatingthe side walls of a given retort in the same direction at the iii'same timeand at arate different from that "of the" corresponding ram in a frequently .re-

curring cycle'relative thereto. 7 l

3. An underfeed stoker comprising retorts having movable sidewalls, -reciprocable rams d for feeding fuel intosaid retorts, .a crank- 1 shaftand connecting rods for driving sald rams,-a wormgear, on said crankshaft, a secnd crankshaft and connecting rods for driv- -ing .'said retort side walls, a orm gear on v said second crankshaft,and a rotatable shaft having" Worms thereon in mesh with said worm gears, sald worms and worm gears beingrso constructed that the crankshafts may be drlven in timed relat on at dlfferent rates. 4. An underfeed stoker comprism'g par shafts at different rates .in a timed frequently recurring cyclic'relatioup- I a 8. An underfeed stoker comprising a retort having a stationary bo ttomand movablexside walls, means for-moving the side walls simultaneously in the same,direction,'tuyeres l mounted on the side walls to move therewith,

a reci'procable ram for feeding fuel into said retort, means for reciprocating the ram" and the side wallsnat different rates in a timed relation and a'frequently recurring cyclic 1 movement, and means for varying the length of stroke of the retort sides independently-i of the length'ofram strokel a v Signed at YVorcester, -Massachusetts, this allel retorts having bottoms andmovable side 7 walls carrying tuyeres thereon, a reciprocable ram to feed the fuel :into each retort, a/ClIlV- mg -mechamsm, connections between said mec'ha'nism and rams to reciprocate'the latter,

andan adjustable lost motion connection be- I tween'said Vmechanism and the side walls which-moves them througha variable distance at a higherrate than the rams move ee and in a frequentlyrecurring cycle relative thereto. j a

5. An underfeed Stoker comprisingretorts having movable side walls, reciprocable rams o 'for feeding fuel to said retorts, a crank shaft 85 and connecting rods for driving said rams, a worm gear on said crank shaftj a second crank shaft and connecting rods for driving said retort side walls, a worm gear on said second crank shaft, and'a rotatable shaft ant-having worms thereon in mesh with said worm gears, said Worms being of opposite hand whereby the thrusts caused by said Wormgears will tend to-counteracteach other.

F An underfeed' stoke'r comprising retorts having stationary bottoms and movable side walls, means for moving the side walls of each" retort simultaneously in the same direction, -tuyeres mounted on the side walls to ;'m0ve therewith, 're'ciprocable rams for feed- 7 50*ing fuel into said retorts,means for reciproeating the rams at one rate and the side walls at a' different rate .in a frequently recurring cyclic relatiQnship, and 'Qverfeed grate sec-' ngtions forming continuations of said bottoms t which grates aretconnected to said sidewalls and arranged toreciprocate therewith. 7 37, An underfeed stoker comprising retorts "having movableside walls, reciprocable rams liter.feeding;fuel-'into said rtortafa cra kshaft and connecting rods-for driving said rams, gase'parate crankshaft and connecting. rods for, driving said retort side walls,- means for adjusting the length of stroke of said rea i6 tort sides. and means for driving said crankthe will ofR. Sanford-Riley, 

